Unit
CELL CYCLE AND DEVELOPMENT UNIT
Description
Connections between cell cycle regulators and developmental programs in simple eukaryotic organismses
How growth and cell cycle progression are coordinately regulated during development in eukaryotic organisms is an active area of research. Extensive studies have led to a thorough understanding of the core mechanisms that drive the eukaryotic cell cycle. It has also become increasingly clear that these core mechanisms are modulated during development. Moreover, cell cycle regulators can in turn impart cell fate during development. The main idea we are trying to address is to assume that cell cycle regulators could have in eukaryotic cells new roles dedicated to determine developmental decisions. To proof the concept, we are using two distinct models of simple eukaryotic organisms: the phytopathogenic fungus Ustilago maydis and the nematode Caenorhabditis elegans.
The fungus U. maydis is perfectly suited to analyze the relationships between cell cycle, morphogenesis and pathogenicity. In this model system the activation of the virulence program involves the mating of a pair of compatible haploid budding cells to produce an infectious dikaryotic hypha. This process implies strong morphological changes (bud to hypha transition) as well as genetic changes (haploid to dikaryotic transition), advocating for an accurate control of the cell cycle and morphogenesis during these transitions. Our starting hypothesis is that the induction of the infective filament in U. maydis, the first step in the pathogenic process, relies on a dual process that involves by one side a specific cell cycle arrest and in other side the specific activation of a hyperpolarization growth. We believe that the impairment of any of these processes will have as an outcome the inhibition of the virulence. Our approaches involve three main objectives:
1) To study the mechanisms responsible of cell cycle arrest during infective filament formation.
2) To study how polar growth is regulated during the induction of the infective filament.
3) To study how the signal emanating from the transcriptional virulence program is transmitted to the cell cycle and morphogenetic regulators
El segundo sistema modelo que estamos usando es C. elegans, que ofrece grandes ventajas para estudiar el control de la división celular durante el desarrollo animal. C. elegans tiene un cuerpo transparente y se desarrolla desde el zigoto de una célula hasta la etapa adulta a través de un patrón de divisiones casi invariante. Por lo tanto, la división de todas las células somáticas se puede seguir dentro de los animales en desarrollo y se conocen los tiempos exactos de la división celular. En combinación con una genética eficiente, esto permite una identificación sensible de mutantes del ciclo celular y un análisis cuantitativo de los defectos de división celular en una resolución que supera las posibilidades en otros modelos animales. Nos centramos en el análisis de las conexiones entre la regulación del ciclo celular y los reguladores de la cromatina, ya que tanto el establecimiento como el mantenimiento de los distintos destinos celulares implican el ajuste del ciclo celular y la formación de cromatina específica.
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